I prefer the term "fulfillment" over "replacement" because when the Bible speaks of the forming of the church it speaks of its makings being connected with the promises of Israel. The term "replacement" doesn't give the impression that the church is a "fulfillment" of Israel but makes it seem as if the church is an outside force that kicks Israel to the side, along with its promises. I believe the term "fulfillment" to be a better term because anytime the Bible speaks of the forming of the church it speaks of its members being heirs of the promises of Israel. If anything, the church is an inside force sprouting out of Israel, who are partakers of the promises of Israel in their fullest and most significant form. The church's connection with Jesus Christ is what puts them in such a position. Jesus sprouted out of Israel to fulfill and become the heir of all the promises of Israel and it is because He is the inside force that the church, His body, is given their fulfilling position.
(Rom 11, Gal 3, Eph 2)